1. Field of the Invention
The present invention relates to an optical disc reproducing apparatus and a recording medium.
2. Description of the Related Art
At present, an optical disc apparatus is prevailing that reads data recorded on an optical disc (a CD (Compact Disc), a DVD (Digital Versatile Disc), etc.) based on an instruction signal that a host computer, etc., receives to execute reproducing of information, and outputs the host computer, etc. Referring to FIGS. 9 and 10, description will be given below for transmission, reception, etc., of data between a host computer 101 and an optical disc apparatus 100. FIG. 9 is a simplified block diagram of an example of the configuration of the optical disc apparatus 100. FIG. 10 is a diagram of a sector cluster (sectors X(0) to W(n)) that is the unit of reproducing or recording of the information, disposed on a track formed in a spiral on an optical disc 102.
When the host computer 101 reproduces the information based on data recorded in, for example, the sectors X(0) to X(2) on the optical disc 102, the host computer 101 transmits an instruction signal to instruct to read the data recorded in the sector X(0) at the head to obtain information indicating the data length and the header of the data generally recorded on the optical disc 102.
When a microcomputer 103 of the optical disc apparatus 100 receives the instruction signal from the host computer 101, the microcomputer 103 transmits a control signal to a servo controlling unit 105 to cause a laser light beam emitted by an optical pickup 104 to be applied to the sector X(0) that the instruction signal designates. The servo controlling unit 105 applies a controlling voltage to a thread mechanism and an actuator that are not shown based on the control signal and, thereby, moves the optical pickup 104 in the radial direction (seeking operation). As a result, the track on which the sector X(0) is disposed and the optical pickup 104 face each other on the optical axis. Therefore, a reflected light beam of the laser light beam that is applied to pits indicating data recorded on the sector X(0), enters the optical pickup 104. A signal corresponding to the light amount of the reflected light beam of the laser light beam from the optical pickup 104, is applied with a predetermined calculating process in a signal processing unit 107. A buffer memory 106 stores the data obtained as the result of the calculating process, etc., (that is, data recorded in the sector X(0)). When the microcomputer 103 determines that data indicating the address of the sector X(0) is present in the data stored by the buffer memory 106, the microcomputer 103 reads the data from the buffer memory 106 and transmits the data to the host computer 101.
The host computer 101 applies a predetermined reproducing process to the data from the optical disc apparatus 100 and, thereby, obtains the information on the data length and the header and, for example, reproduces music information, image information, etc. The host computer 101 transmits an instruction signal that designates the sectors X(1) and X(2) to the optical disc apparatus 100 to read data recorded in the sectors X(1) and X(2) following the sector X(0).
The microcomputer 103 of the optical disc apparatus 100 transmits a control signal to a servo controlling unit 105 to cause the laser light beam emitted from the optical pickup 104 to be incident on the sectors X(1) and X(2) that the instruction signal designates based on the instruction signal from the host computer 101. The servo controlling unit 105 applies a controlling voltage to the above thread mechanism and the actuator based on the control signal and, thereby, moves again the optical pickup 104 in the radial direction. By repeating the above processes, the data recorded in the sectors X(1) and X(2) is transmitted to the host computer 101. As a result, based on the data recorded in the sectors X(1) and X(2) following the sector X(0), reproduction of music information, reproduction of image information, etc., are executed.
In this manner, in a conventional optical disc apparatus 100, the optical pickup 104 is moved in the radial direction to a sector designated by an instruction signal every time the instruction signal is received from the host computer 101, and the data recorded in the sector is read (see, for example, Japanese Patent Application Laid-Open Publication No. 2003-330623 and Japanese Patent Application Laid-Open Publication No. 1999-143644).
However, because the optical pickup is moved to a sector designated by an instruction signal every time the instruction signal is received from the host computer, the time taken for the moving process and the time taken for the processing of the signal after the move are necessary. Therefore, the time necessary for the optical disc apparatus to read the data may be long. As a result, for example, transmission of data from the optical disc apparatus to the host computer is delayed. Therefore, problems may arise that the reproducing process in the host computer can not be executed continuously, etc. Therefore, a user who uses optical discs may feel inconvenience.